Chromatography Forum

I'm currently a student who is having trouble grasping some of the basic principals of GC. Perhaps you could help me, and any help is great appreciated.

So I'm setting up a column (we're goin low tech with home made GC), neatly packed with what I am told to be polar "tide- yeah.. the cleaning stuff" pebbles. Now, everything is moving smoothly and I obtain my results (we're injecting freon21/22/ch2cl2).


methane is the carrier gas, and we're observing our retention times with the beilstein effect (flame at end of GC).

So, here are my questions..

1) I'm told that the reason why the freon gasses have different retention times ARE not because of polarity in the tide pebbles... how is this possible?
2) if it is not polarity which affects retention times, then, what is it within the freon 21/22 which cause it do burn at different rates?

3) we did several tests where we mixed several gasses together, how would this affect each retention time? would they mirror times as if we did them seperately?

any help is much appreciated and thanks in advance!

1) I'm told that the reason why the freon gasses have different retention times ARE not because of polarity in the tide pebbles... how is this possible?
2) if it is not polarity which affects retention times, then, what is it within the freon 21/22 which cause it do burn at different rates?

I'll make you work for the answer. You've gotta look at it from the point of view of the sample. What kind of differences are there between the Freon 21 and 22 (differences in their properties)?